1. Field of the Invention
The invention relates to a method of manufacturing a heat exchanger designed to cool at least one power electronic component. The invention also relates to such a heat exchanger.
2. Brief Description of the Related Art
Heat exchangers are used conventionally to avoid detrimental overheating of power electronic components, such as Insulated Gate Bipolar Transistor (IGBT) circuits or equivalent equipments. As described in Document FR-A-2 777 986, such a heat exchanger can comprise a plate on which tubes are mounted through which a coolant fluid circulates. As envisaged in US-A-2004/0000391, such a heat exchanger can further comprise a metal base on which graphite fins are mounted, those fins being engaged in grooves that are machined in the base. Even when a friction fit is used, the mechanical fastening of those fins is not permanent, in particular insofar as the successive increases in the temperature of the base give rise to variations in the dimensions thereof that do not correspond to the changes in the fins. Therefore, the thermal contact between the fins and the base tends to deteriorate over time, which adversely affects the overall effectiveness of the heat exchanger.
When making a heat exchanger that comprises a metal base, and fins of high thermal conductivity (expressed in watts per meter degree Celsius (W/m° C.)), a problem arises concerning how to fasten together the various elements of different natures. The fins can be assembled mechanically onto the base, with the above-mentioned drawbacks, by brazing or by adhesive bonding. Fastening by brazing guarantees heat transfer that is of good quality, which is desirable in applications in which maximum cooling effectiveness is desired. However, that solution suffers from the drawback of requiring coatings to be applied to the parts that are to be assembled prior to assembly thereof, those coatings often being costly in view of the uses for which they are designed. In addition, the nature of certain fin materials does not make it possible to accommodate such treatments and/or to withstand the increase in temperature resulting from the brazing. Adhesive bonding is sometimes applied. In which case, the thermal improvement procured by the material of the fin is, for the most part, lost in the adhesive bond in which the thermal conductivity of the products used is very low.